diff --git a/calc.go b/calc.go
index f3892fca..3c449492 100644
--- a/calc.go
+++ b/calc.go
@@ -13282,24 +13282,13 @@ func (fn *formulaFuncs) CONCATENATE(argsList *list.List) formulaArg {
 // concat is an implementation of the formula functions CONCAT and
 // CONCATENATE.
 func (fn *formulaFuncs) concat(name string, argsList *list.List) formulaArg {
-	buf := bytes.Buffer{}
+	var buf bytes.Buffer
 	for arg := argsList.Front(); arg != nil; arg = arg.Next() {
-		token := arg.Value.(formulaArg)
-		switch token.Type {
-		case ArgString:
-			buf.WriteString(token.String)
-		case ArgNumber:
-			if token.Boolean {
-				if token.Number == 0 {
-					buf.WriteString("FALSE")
-				} else {
-					buf.WriteString("TRUE")
-				}
-			} else {
-				buf.WriteString(token.Value())
+		for _, cell := range arg.Value.(formulaArg).ToList() {
+			if cell.Type == ArgError {
+				return cell
 			}
-		default:
-			return newErrorFormulaArg(formulaErrorVALUE, fmt.Sprintf("%s requires arguments to be strings", name))
+			buf.WriteString(cell.Value())
 		}
 	}
 	return newStringFormulaArg(buf.String())
diff --git a/calc_test.go b/calc_test.go
index 607289f2..24c6efa3 100644
--- a/calc_test.go
+++ b/calc_test.go
@@ -1663,8 +1663,12 @@ func TestCalcCellValue(t *testing.T) {
 		"=CODE(\"\")":      "0",
 		// CONCAT
 		"=CONCAT(TRUE(),1,FALSE(),\"0\",INT(2))": "TRUE1FALSE02",
+		"=CONCAT(MUNIT(2))":                      "1001",
+		"=CONCAT(A1:B2)":                         "1425",
 		// CONCATENATE
 		"=CONCATENATE(TRUE(),1,FALSE(),\"0\",INT(2))": "TRUE1FALSE02",
+		"=CONCATENATE(MUNIT(2))":                      "1001",
+		"=CONCATENATE(A1:B2)":                         "1425",
 		// EXACT
 		"=EXACT(1,\"1\")":     "TRUE",
 		"=EXACT(1,1)":         "TRUE",
@@ -3665,9 +3669,11 @@ func TestCalcCellValue(t *testing.T) {
 		"=CODE()":    {"#VALUE!", "CODE requires 1 argument"},
 		"=CODE(1,2)": {"#VALUE!", "CODE requires 1 argument"},
 		// CONCAT
-		"=CONCAT(MUNIT(2))": {"#VALUE!", "CONCAT requires arguments to be strings"},
+		"=CONCAT(NA())":  {"#N/A", "#N/A"},
+		"=CONCAT(1,1/0)": {"#DIV/0!", "#DIV/0!"},
 		// CONCATENATE
-		"=CONCATENATE(MUNIT(2))": {"#VALUE!", "CONCATENATE requires arguments to be strings"},
+		"=CONCATENATE(NA())":  {"#N/A", "#N/A"},
+		"=CONCATENATE(1,1/0)": {"#DIV/0!", "#DIV/0!"},
 		// EXACT
 		"=EXACT()":      {"#VALUE!", "EXACT requires 2 arguments"},
 		"=EXACT(1,2,3)": {"#VALUE!", "EXACT requires 2 arguments"},